Nikon D5300 Focus

[pmac1A]

ok, so reading the instruction manual, it says "Turn the Auto Focus OFF on the camera body and lens if you are using photo lens"

on my d5300, the only way I can do that is on the info menu, by changing focus to MF which I did. My lens does not have an AF/MF switch on it. So when I go for the focus screen, it acts as if my lens is not recognised and I do not see the arrow focus buttons on the screen

If however on my info screen I select AF mode (either AF-S or any of the AF modes), then the BYN screen shows the fine focusing buttons, etc

Is that normal? I thought that we had to select all focus to manual etc?

I did look at the user guide pdf but couldn't find the answer

Thanks

[pmac1A]

The Reason for asking is that if I leave the camera on any form of AF, it will not be able to achieve focus on any star at night. So do I leave it in AF mode S (single servo), C (continuous servo), A (auto-servo), so I get the BYN focus screen, and then through the BYN screen try to achieve focus?

Won't that make the lens just "hunt" for focus all the time?

[astroman133]

If the lens is in Manual Focus mode then the lens servo cannot be driven by the camera or BYN. So in order to focus the lens it needs to be in Auto Focus mode.

However, it is common that pressing the shutter button part way down forces the camera to attempt to adjust focus. This re-focus action also happens when BYN attempts to take a picture. This behavior won't work when shooting wide field night sky scenes because there is not enough light for AF to work and so the lens needs to be in MF mode for imaging.

So, basically you need to be able to focus some times but not others. You could put the lens in AF mode to focus. Then tape the focus ring on the lens so that it will stay in focus and put it in MF mode for imaging. You may also be able to remap the autofocus functionality to another button. With my Canon, for example, I can map the AF functionality to the Zoom- button.

[pmac1A]

Thank you for your answer. That kind of defeats my purpose for trying BYN as I wanted to control the camera remotely without having to refocus. also I want to do widefield scenes with a fast 50mm f1 lens or maybe some 70mm f4 shots, so in both cases there won't be enough light for AF to work. I though somehow BYN would help me with that instead of my trial and error MF routine at the moment.

That basically reduces the purpose of BYN to programming a sequence of images being taken, still very nice don't get me wrong but lack of focus control is a downer for me

 

also I noticed when in AF mode, even the smaller increment on the BYN focus (the single arrow) makes a huge change compared to if I was focusing in manual mode so even with the single arrows, even with one touch on either button you find yourself totally out of focus

 

[admin]

BYN cannot perform a function that is not supported by the camera / lens combo.  We have to remember that a DSLR is primarily designed for daytime photography.  This said, as mentioned earlier, the lens motor are engaged only when set to AF.  For daytime this makes sense, for nighttime (and remote imaging) this is sadly counter productive